Air purifier having ultraviolet disinfection means

ABSTRACT

The present invention provides an air purifier that purifies, disinfect and decontaminate convention air flow by using UV rays. Because the UV rays emitted by the UV light sources are contained within the air purifier, use of the air purifier is safe in that a nearby person can avoid exposure to hazardous UV radiation. Adjustment of operating conditions, such as the UV intensity and wavelength and air speed, is programmable via a remote controller, a smart switch, a smart device, a wireless communication device, a smart home control appliance, a sensing device, and/or a built-in module, which renders the air purifier a smart appliance that may automatically and optimally suits to a user&#39;s need based on the user&#39;s habit and other physical parameters. Installation and removal of the air purifier, as well as cleaning and replacement of any part thereof, are simple and convenient, as a result of the clever design.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefits of U.S. Ser. No. 63/045,069, filedJun. 27, 2020. The entire contents and disclosures of the priorapplication are incorporated herein by reference into this application.

Throughout this application, various references are referred to anddisclosures of these publications in their entireties are herebyincorporated by reference into this application to more fully describethe state of the art to which this invention pertains.

FIELD OF THE INVENTION

The present invention relates to air purifiers that include disinfectionand/or decontamination by ultraviolet (UV) radiation.

BACKGROUND OF THE INVENTION

Ultraviolet radiation can be utilized for germicidal disinfection anddecontamination of air and surfaces. UV radiation is the electromagneticradiation that falls in the region of spectrum between visible light andx-rays. UV radiation is invisible to the human eye and includeswavelengths in the spectral range of 100 to 400 nanometers (nm). Thisspectral range can be subdivided into four regions: vacuum UV rays withwavelengths in the range of 100 to 200 nm, UVC rays with wavelengthsthat range from 200 to 280 nm, UVB rays with wavelengths that range from280 to 315 nm, and UVA rays with wavelengths that range from 315 nm to400 nm. Because of the spectral sensitivity of the DNA and RNA inbacteria and viruses, only the UVC region demonstrates significantgermicidal properties. According to the 2006 U.S. EPA UV DisinfectionGuidance Manual (1), recommended UVC exposure dosage, which is measuredas the product of UVC light intensity multiplied by exposure time,should be at least 2,500 μW·s/cm² and up to 8,000 μW·s/cm² foreffectively killing 90% of most bacteria and viruses.

Conventional devices using UV radiation for disinfection and/ordecontamination, such as low-pressure UV lights and/or UV lamps, maypresent problems with safety and effectiveness. Extensive and prolongedexposure to UV radiation may be associated with occurrence of skincancers and may also cause health problems to the eyes. Theeffectiveness index of a conventional UV lamp is typically around 80%,which does not put the UVC region to most effective use. The presentinvention addresses the foregoing issues with innovative designs andoptimal spectral tuning.

SUMMARY OF THE INVENTION

The present invention provides an air purification system comprising amulti-piece rigid housing having a detachable inlet for receiving air, adetachable outlet for exhausting air, and one or more utility openings,wherein a stream of air is passable from the inlet to the outlet; a UVlight subsystem fitting the outlet and comprising a plurality of UVlight sources that are configured to emit UV radiation with adjustablewavelengths to irradiate a stream of air in the interior of the airpurification system; an air convection means configured to continuouslymove a stream of air (a) through the inlet from outside into theinterior of the air purification system, (b) within the air purificationsystem, from the inlet towards the outlet, and (c) through the outlet,from the interior to outside the air purification system; an airfiltration means fitting the inlet and configured to remove particulatesfrom a stream of air; an operation control subsystem having a pluralityof control functions and configured to control the air purificationsystem's operating status including the status of the air purificationsystem and the status of any component of the air purification system,wherein the UV light subsystem, the air convection means, the airfiltration means, and the operation control subsystem are enclosed bythe housing; the operation control subsystem is adapted to the utilityopenings, through which an operator of the air purification system canaccess the control functions; when the air purification system isoperating, a stream of air moved by the air convection means enters theinterior of the air purification system, is irradiated by the UV lightsources and filtered by the air filtration means, and exits the airpurification system via the outlet, thereby being purified, disinfectedand decontaminated by the air purification system.

The air purification system of the present invention may furthercomprise a UV sensor and motion sensors such as High Frequency Doppler(HFD) sensors inside the housing.

In one embodiment, the UV radiation emitted by the UV LED light sourcesis in the wavelength range of 200 nm to 400 nm. In one embodiment, theUV radiation emitted by the UV LED light sources is in the wavelengthrange of 240 nm to 290 nm. In another embodiment, the UV radiationemitted by the UV LED light sources has peak wavelength range of 260 nmto 270 nm. In one embodiment, the UV radiation emitted by the UV LEDlight sources has a wavelength of approximately 405 nm, which is bothvisible to the human eye and effective for bacterial decontamination. Inone embodiment, the UV radiation emitted by the UV LED light sourcesbreak down and inactivate infectious organisms such as bacteria,viruses, and other pathogens, and thereby disinfects and decontaminatesair and surrounding surfaces.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a front perspective view of the air purification system inaccordance with the present invention.

FIG. 2 is a rear perspective view of the air purification system inaccordance with the present invention.

FIG. 3 is an exploded view of the air purification system in accordancewith the present invention.

FIG. 4 is an exploded perspective view of the air purification system inaccordance with the present invention.

FIG. 5 is an exploded perspective view of the air purification system inaccordance with the present invention.

FIG. 6 is a flow diagram illustrating a stream of air passing throughthe air purification system in accordance with the present invention.

FIG. 7 is an electrical diagram illustrating the operating electricalconnections of the air purification system in accordance with thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides an air purification system (100)comprising a multi-piece rigid housing (101) having a detachable inlet(102) for receiving air, a detachable outlet (103) for exhausting, andone or more utility openings (104), wherein a stream of air is passablefrom the inlet (102) to the outlet (103); a UV light subsystem (105)fitting the outlet (103) and comprising a plurality of UV light sources(106) that are configured to emit UV radiation with adjustablewavelengths to irradiate a stream of air in the interior of the airpurification system (100); an air convection means (107) configured tocontinuously move a stream of air (a) through the inlet (102) fromoutside into the interior of the air purification system (100), (b)within the air purification system (100), from the inlet (102) towardsthe outlet (103), and (c) through the outlet (103), from the interior tooutside the air purification system (100); an air filtration means (108)adjacent to the inlet (102) and configured to remove particulates from astream of air; an operation control subsystem (109) having a pluralityof control functions and configured to control the air purificationsystem's (100) operating status including the status of the airpurification system (100) and the status of any component of the airpurification system (100), wherein the UV light subsystem (105), the airconvection means (107), the air filtration means (108), and theoperation control subsystem (109) are enclosed by the housing (101); theoperation control subsystem (109) is adapted to the utility openings(104), through which a user of the air purification system (100) canaccess the control functions; when the air purification system (100) isoperating, a stream of air moved by the air convection means (107)enters the interior of the air purification system (100), is irradiatedby the UV light sources (106), filtered by the air filtration means(108), and exits the air purification system (100) via the outlet (103),thereby being purified, disinfected and decontaminated by the airpurification system (100).

The air purification system (100) of the present invention may furthercomprise a UV sensor and motion sensors such as High Frequency Doppler(HFD) sensors inside the housing (101).

The following terms shall be used to describe the present invention. Inthe absence of a specific definition set forth herein, the terms used todescribe the present invention shall be given their common meaning asunderstood by those of ordinary skill in the art.

The housing (101) is an enclosure protecting internal components, suchas the UV light subsystem (105), the air convection means (107), the airfiltration means (108), and the operation control subsystem (109). Inone embodiment, the housing (101) is made of metal, plastic, and/orother materials, depending on actual needs in practice and use. In oneembodiment, the housing (101) is manufactured in several constituentpieces that are assembled together to form the entire housing (101). Asillustrated in FIGS. 3 and 4, the inlet (102) and the outlet (103) are,for example, two of the constituent pieces and are embedded in thehousing (101). In one embodiment, the housing (101) includes a frontsection (200) and a rear section (201), with the inlet (102) embedded onthe top of the rear section (201) and the outlet (103) embedded at thebottom of the front section (200), although the location of the inlet(102) and the outlet (103) may be arranged differently in accordancewith design preference. The housing (101) has one or more utilityopenings (104) that fit signal receivers, control panels/interfaces,and/or switches for the internal operation control subsystem (109), toallow a user's access to the control functions. In one embodiment, thehousing (101) is designed to feature mounting holes on the surface ofthe housing (101), which facilitate easy installation onto and removalfrom a wall or celling.

The inlet (102) is a set of slits detachably embedded in the housing(101) and allows air to enter from outside into the interior of the airpurification system (100). The slit width and spacing can vary,depending on actual needs in practice and use.

The outlet (103) is a set of slits detachably embedded in the housing(101) and allows air to exhaust from the interior to outside the airpurification system (100). The slit width and spacing can vary,depending on actual needs in practice and use. A disinfection chamber isdefined as the space occupied by a stream of air from the air convectionmeans (107) to the outlet (103), where UV disinfection of the stream ofair occurs.

The utility openings (104) may be carve-outs that are designed andmanufactured in the housing (101) or on the constituent pieces thereof.As illustrated in FIG. 5, the utility openings (104) are configured andadapted to fit various panels, interfaces and/or switches of theoperation control subsystem (109). Location and dimension of each of theutility openings (104) can be adjusted during the manufacturing process,depending on actual needs in practice and use.

The UV light subsystem (105) comprises UV light sources (106) that areassembled on a UV light substrate, and any circuitry for electricalpower and control thereof. In one embodiment, the UV light substrate isa printed circuit board (PCB) onto which UV LEDs (106) are solderedtogether with an electronic component for controlling the UV LEDs (106).

Aluminum has excellent thermal conductivity. In one embodiment, the UVlight substrate is a PCB, and its main ingredient comprises aluminum foroptimal heat dissipation. Heat generated by the UV light sources (106)can quickly be transferred to the aluminum PCB, and further to theconvention air exhausted through the outlet (103), so that the operatingtemperature of the UV light sources (106) is maintained at a level thatprolongs their longevity. In one embodiment, the aluminum PCB preventsthe UV LED light sources (106) from overheating and maintains theiroperating temperature within a specified normal range during extensiveuse.

In one embodiment, the UV light sources (106) are UV LEDs soldered onone or more PCBs, and the PCBs are mounted within the disinfectionchamber and next to the outlet (103), such that a stream of air isirradiated by the UV rays emitted by the UV LEDs (106) before it isexhausted through the outlet (103). The PCBs are rectangle in shape, andthe UV LEDs (106) are arranged in a regular grid pattern with fixedspacing along the length and width of the PCBs. An integrated circuitchip, i.e., the electronic component, is also soldered on each of thePCBs to convert commercial power into a power supply for the UV LEDs(106). The integrated circuit chips receive control commands from theoperation control subsystem (109). The integrated circuit chips aredirectly connected to the UV LEDs (106) and control the On/Off states,intensity and wavelengths of the UV LEDs (106).

The UV light sources (106) are chosen to emit desired opticalwavelengths in the ultraviolet spectrum. The UV light sources (106) areenclosed inside the air purification system (100) by the housing (101)and arranged in a predetermined pattern (e.g., strip, panel, latticegrid, etc.) that is desired in practice and use, usually with a fixedspacing for uniform illumination. When powered on, the UV light sources(106) emit UV light that projects outwards, irradiates the interior ofthe air purification system (100), and disinfects and/or decontaminatesair passing through the system to cleanse the surrounding area. In oneembodiment, the UV light sources (106) are ultraviolet light-emittingdiodes (UV LEDs) including LEDs for emitting UVC rays (e.g., UVC LEDswith a spectrum of wavelengths centered at approximately 265 nm) andnear UVA rays (e.g., Near UVA LEDs with a wavelength of approximately405 nm). In one embodiment, the UV light sources (106) are UV LEDs, andeach UV LED comprises two or more LED chips combined into a single LEDcomponent, such that each UV LED emits both UVC rays with a centerwavelength of approximately 265 nm and near UVA rays with a wavelengthof approximately 405 nm simultaneously. In one embodiment, the UV lightsources (106) comprise UVC LEDs and Near UVA LEDs that are assembled,e.g., soldered, onto one or more PCBs in any desired combination thatdepends on actual needs in practice and use, wherein the UVC LEDs emitUVC rays with a center wavelength of approximately 265 nm, and the NearUVA LEDs emit near UVA rays with a wavelength of approximately 405 nm,allowing flexibility in the selection and/or manipulation of a desiredspectrum of wavelengths.

Existing technology for air disinfection by UV radiation, such asconventional UV lamps and UV lights, often resorts to ultraviolet quartzsleeves and tubes powered by external ballasts as the source of UV rays.Compared to the present invention using UV LEDs (e.g., UVC LEDs and NearUVA LEDs) (106), the existing technology has disadvantages due to largerdimension of the UV sleeves, fewer choices of the sleeve shape, moreoverheating, shorter life span, and the like, so available designs areless flexible and limited. The present invention adopts UV LEDs (106)which are much smaller in volume, generate less heat in operation, andlast longer in use. The UV LEDs (106) may be assembled alongside theintegrated circuit chip onto one PCB assembly that is the core of the UVlight subsystem (105). As a single component, the UV light subsystem(105) can be as small, light-weight and compact as possible to open uppossibilities for innovative designs and attractive shapes of the airpurification system (100).

The UV light sources (106) can be arranged and assembled on panels, suchas on UV light substrates. In one embodiment, one UV light substratecomprising a number of UV LEDs (106) is placed near the outlet (103),such that the UV rays emitted by the UV LEDs (106) may irradiate thestream of air when it is exhausted through the outlet (103). Using onlyone UV light substrate reduces cost of energy. In another embodiment,two UV light substrates, each comprising a number of UV LEDs (106), areplaced in parallel near the outlet (103), such that the stream of air issandwiched in between the substrates and is irradiated by the UV raysemitted by the UV LEDs (106). Using two or more substrates of UV LEDs(106) leads to quick and effective air disinfection.

In one embodiment, the UV light sources (106) are UV LEDs (106) thathave a rated life of up to 30,000 to 50,000 hours (measured as the timeof use after which the UV LEDs optical output decreases to 70% of theoriginal value), which is about 2.5 to 5 times superior to that oftypical quartz tubes. In comparison, the rated life of quartz tubes istypically under 12,000 hours.

The brightness, effectiveness and longevity of UV LEDs (106) areinversely proportional to their operating temperature. In oneembodiment, the lifetime or longevity of the UV LEDs (106), can beincreased by using a large number of such UV LEDs (106) operating at anelectrical power lower than the nominal power output, so as to reducethe produced heat and maintain the UV light subsystem (105) at anoperating temperature that prevents overheating. In one embodiment, thelifetime or longevity of the UV LEDs (106), is increased to 200% oftheir rated life, by operating at an electrical power equal to 50% oftheir nominal power.

In one embodiment, the air purification system (100) further comprises aUVC sensor near the UV light subsystem (105) inside the housing (101),for detecting the intensity of UVC rays emitted by the UV light sources(106) in the interior of the air purification system (100). In oneembodiment, based on sensory data received from the UVC sensor, the airpurification system (100) automatically modulates the electric powersupplied to the UV light sources (106) so as to maintain a constantlevel of UVC intensity in the interior of the air purification system(100). In one embodiment, the electrical power supplied to brand-new UVlight sources (106) is 70% of the nominal power supply of the UV lightsources (106), and, after use for a period time and when the UVC sensordetects a 10% reduction of the intensity of UVC rays in the interior ofthe air purification system (100), the air purification system (100)automatically modulates the electrical power supplied to the UV lightsources (106) to 80% of their nominal power supply. In one embodiment,by modulating the electrical power supplied to the UV light sources(106), the longevity of the UV light sources (106) can be increased, andthe UVC intensity is maintained at a constant level during the use ofthe air purification system (100).

In one embodiment, the UV light sources (106) have peak wavelengths inthe range of approximately 265 nm for optimal disinfection anddecontamination. In one embodiment, the UV light sources (e.g., UVand/or UVC LEDs) (106) have peak wavelengths in the range of 260 to 270nm and total optical power output of at least 60 to 80 mW when operatingat 500 mA.

In one embodiment, while emitting UVC rays, the UV light sources (106)further comprise UVA LEDs (106) configured to emit near UVA rays at anapproximate wavelength of 405 nm. Near UVA rays at a wavelength ofapproximately 405 nm are visible to the human eye, and theirbactericidal effects, i.e., inactivation of bacteria such asEscherichia, Salmonella, Shigella, Listeria, and Mycobacterium speciesare demonstrated by a previous study (2).

Conventional UV disinfection systems rely on UVC radiation at awavelength of approximately 254 nm and may only achieve a PeakGermicidal Disinfection Effectiveness (PGDE) Index of approximately 80%.Compared to those conventional systems, the air purification system(100) of the present invention optimally tunes the wavelength of UVCradiation in the range of 250 to 300 nm to a peak wavelength ofapproximately 265 nm, so that it can achieve a PGDE Index of almost100%.

In one embodiment, the UV light sources (106) are UV LEDs, and each UVLED may attain a viewing angle of 130 degrees, a forward voltage between5.0 and 9.0 V when operating at 500 mA, a junction-to-case thermalresistance of 7.0° C./W, and a power dissipation of 4.0 W or no greaterthan 4.5 W when operating at 500 mA.

In one embodiment, the UV light sources (106) can tolerate a continuousforward current of 100 to 700 mA or of 500 mA, a reverse voltage of nohigher than about 5 V, a case temperature in the range of −10 to 80° C.when operating at 500 mA, a storage temperature of −40 to 100° C., and ajunction temperature no higher than 115° C.

In one embodiment, the UV light sources (106) have preheat or soaktemperature between limit temperatures of 150° C. (T_(smin)) and 200° C.(T_(smax)), and time for transition between the limit temperatures is 60to 120 seconds. The UV light sources (106) have a liquidus temperature(T_(L)) of approximately 217° C., a maximum peak package bodytemperature (T_(P)) of 260° C., a maximum ramp-up rate of 3° C./s, and atime maintained above T_(L) of 60 to 150 seconds (t_(L)). The UV lightsources (106) have a maximum ramp-down rate of 6° C./s from T_(P) toT_(L) and a maximum time of approximately 8 minutes from 25° C. toT_(P).

In one embodiment, the UV light sources (106) have a power of 30 to 150W, a flux of 10 to 10,000 μW/cm² so as to achieve a UVC exposure dosageof at least 2,500 μW·s/cm² in the interior of the air purificationsystem (100) within several seconds to several minutes of use, and anirradiation of 200 to 3,000 mW which is a high UV intensity for fast andeffective disinfection and decontamination of an airstream as discussedbelow.

Compared to conventional UV disinfection systems, the air purificationsystem (100) of the present invention provides safety protection of aperson nearby from UV hazard, such as protecting a nearby person's eyehealth, by a clever design that contains the UV light sources (106) andUV rays emitted thereby within the enclosure. Exposure to UV radiationcan be dangerous and associated with damage to eyesight and incidence ofskin cancers, and a person adjacent to UV systems should be protectedfrom direct exposure of UV radiation. When operating and emitting UVCradiation, the air purification system (100) of the present inventionprevents the UV rays from propagating outside the air purificationsystem (100) to avoid exposing a nearby person to the UV radiation.Since UV rays inside the air purification system (100) are invisible tothe person nearby, safety of use of the air purification system (100) isenhanced. The Near UVA rays emitted by the Near UVA LEDs (106) are anindicator and deterrent, and they serve as a safety measure when a userintentionally or accidentally opens the housing (101) during the airpurification system's (100) operation. Observing the near UVA rays, theuser, or a nearby person, can be alerted and turn off the UV rays toavoid extensive exposure.

UV rays emitted by the UV light sources (106) in the present inventionirradiate only the interior of the air purification system (100) and donot spread into space outside the air purification system (100), so aperson near the air purification system (100) is protected againstunsafe UV radiation. In one embodiment of the present invention, whenthe air purification system (100) is operating, UV rays cannot bedetected in the outside space in proximity to the air purificationsystem (100). In one embodiment of the present invention, when the airpurification system (100) is operating, UV rays detected in theproximity of the air purification system (100) are less than 0.1% of thetotal optical power of the UV light sources (106), i.e., less than 0.1μW/cm², corresponding to an absolute safe level for extensive use byhuman.

The air convection means (107) moves air to flow through the inlet (102)and outlet (103) on the housing (101) and within the interior of the airpurification system (100). When operating, the air convection means(107) generates an air pressure ingredient that causes air to enterthrough the inlet (102) on the housing (101) into the interior of theair purification system (100), pass within the air purification system(100) from the inlet (102) towards the outlet (103), and exits the airpurification system (100) through the outlet (103) on the housing (101).With the air convection means (107), a stream of air is drawn from thesurrounding space and circulated through the air purification system(100) for purification, disinfection and decontamination, before itexits and returns to surrounding space. The air convection means (107)has an adjustable operating power, so that it may run at a low speed, ahigh speed, or any other speed between the two. A low or comfortablynegligible noise is rendered at the low speed, and a high throughput ofair stream is enabled at the high speed, so that the air purificationsystem (100) is suited for use in a large space despite its seeminglysmall form factor. In one embodiment, the air convection means (107) hasa flow rate of up to 50 to 100 cu. ft. per minute, i.e., 50 to 100 CFM,when operating at the high speed. In one embodiment, the air convectionmeans (107) has a flow rate of up to 200 CFM at the high speed, suitingspace of up to 800 sq. ft. In one embodiment, the air convection means(107) has a flow rate of up to 350 CFM at the high speed, suiting spaceof up to 1,200 sq. ft. In one embodiment, the air convection means (107)has a flow rate of up to 400 CFM at the high speed, advantageous for usein space with high ceiling and/or larger area than 1,200 sq. ft. The airconvection means (107) is detachably assembled into the housing (101),facilitating replacement when needed.

In one embodiment, the air convection means (107) is a centrifugal pumpimpeller whose rotation is driven by an AC or DC electric motor (202).In one embodiment, the impeller has 3 to 5 vanes. In another embodiment,the impeller has 7 or more vanes. In one embodiment, the impeller andits driving motor (202) are mounted on an internal mount structureinside the housing (101), wherein the mount structure is rigidlyattached to the inner surface of the housing (101), such as the innersurface of a rear section (201).

In one embodiment, the air convection means (107) is a fan that ispropelled by a small AC or DC electric motor (202). The fan may have 4to 8 blades. In one embodiment, the air convection means (107) maycomprise two fans, one facing the inlet (102) and the other facing theoutlet (103), which operate at the same time for an increased air flow.

In one embodiment, the air convection means (107) allows adjustment ofoperating power between 2 speeds, a high speed for high air flowthroughput, and a low speed for comfortably negligible noise. In oneembodiment, the air convection means (107) allows adjustment ofoperating power among 3 to 5 speeds, wherein the lowest speed renderscomfortably negligible noise, and wherein the air purification system(100) can suit a large space up to 800 sq. ft. at the highest speed. Inone embodiment, several air purification systems (100) of the presentinvention may cooperate at the high speed of the air convection means(107) at the same time, so as to accommodate an indoor space of anysize.

The air filtration means (108) has an identical or similar shape as theinlet (102) of the housing (101) and is detachably attached thereto forremoval of particulates from the air stream. Efficiency of the airfiltration means (108) is increased by running the air convection means(107) at a higher speed. The air filtration means (108) is replaceable,and its easy installation also facilitates regular replacement within acertain period for continuing effectiveness of air decontamination.

In one embodiment, as illustrated in FIG. 5, the air filtration means(108) is an air filter commonly available in home-use or commercial airpurifiers. In one embodiment, the air filtration means (108) is one airfilter attached to and facing the inlet (102) of the housing (101). Inone embodiment, the air filtration means (108) is an HEPA air filter. Inone embodiment, the air filtration means (108) is replaced every month.In one embodiment, the air filtration means (108) is replaced every 3months. In one embodiment, the air filtration means (108) is replacedevery 6 months, depending on operating conditions and filter type.

The operation control subsystem (109) is the central processing andcontrol unit that receives control instructions and sends controlcommands accordingly. The control instructions can be received from oneor more sources including:

-   -   (a) a remote controller using infrared and/or radio frequency;    -   (b) a smart switch directly connected to the air purification        system (100), which is optionally equipped with digital display        of the air purification system's (100) operating status;    -   (c) a transmitting device using wireless communication such as        Wi-Fi and/or Bluetooth technologies;    -   (d) a smart home control appliance including a smart speaker        wirelessly connected to the air purification system (100);    -   (e) a sensing device directly or wirelessly connected to the air        purification system (100); and    -   (f) a programmable module of the air purification system (100).

In one embodiment, the operator control system (109) comprises a driver,for example LED driver, which is an integrated circuit built into theair purification system (100) as illustrated in FIG. 7. The driverreceives electric power from an outlet or other power sources, and it isconfigured to convert and modulate electric power of the UV lightsubsystem (105), the UV light sources (106), the air convection means(107), the AC or DC electric motor, or driving motor (202), the airfiltration means (108), and the control box (203). The LED driver alsosupplies electric power to motion detection sensors and UV sensors,receives sensory signals from these sensors, and sends control commandsto modulate operating conditions of the UV light sources (106) and theair convection means (107).

In one embodiment, the operation control subsystem (109) comprises acontrol box (203) fitting one of the utility openings (104) on thehousing (101). A user can use the control box (203) to switch on or offthe air purification system (100). When the air purification system(100) is switched on, the UV LEDs (106) light up and start emitting UVrays including UVC rays, and, driven by a motor (202), an impellerrotating at a predetermined speed draws air into the disinfectionchamber to be irradiated by the UV LEDs (106) before it exists the airpurification system (100) through the outlet (103). In one embodiment,the operation control subsystem (109) comprises multiple control boxes(203), each fitting one of the utility openings (104) on the housing(101) and controlling certain operating conditions or parameters of theair purification system (100).

The operation control subsystem (109) can power on or off the entire airpurification system (100). Furthermore, by sending control commands, theoperation control subsystem (109) can control the following operatingstatus of the air purification system (100), including the operatingconditions and parameters as follows:

-   -   (a) On/Off state of the UV light subsystem (105);    -   (b) Intensity of the UV rays emitted by the UV light sources        (106);    -   (c) Wavelength of the UV rays emitted by the UV light sources        (106); and    -   (d) Speed of the air convection means (107).

The air purification system (100) of the present invention may furthercomprise a motion sensor that is normally used in a surveillanceapparatus such as a miniaturized security camera. In one embodiment, theair purification system (100) of the present invention comprises a HighFrequency Doppler (HFD) sensor. Sensory signal of the motion sensor canbe image-based, and the motion sensor can include a camera system thatsupports normal camera functionality such as capturing visual images.The sensory input can also be infrared ray-based, and the motion sensorcan include a sensor unit with predetermined field of view. The sensoryinput can further be microwave-based, such as the HFD sensor, to achievesuperior detection range and sensitivity.

In one embodiment, the air purification system (100) of the presentinvention comprises a motion sensor that transmits sensory signalsindicating whether motion of a human is detected within a detectionrange, e.g., 3 to 12 meters. The detection range is tunable duringmanufacturing process and/or field adjustable via a switch or software.With a detection range up to 12 meters, the air purification system(100) can accommodate a large space with a high ceiling, such as hotellobbies, large warehouses, or factories. In one embodiment, the airpurification system (100) comprises a motion sensor with a maximumdetection range of up to 12 meters. In one embodiment, the airpurification system (100) comprises a motion sensor whose detectionrange can be field adjusted from 10% to 100% of the maximum detectionrange. In one embodiment, the air purification system (100) comprises amotion sensor whose detection range can be field adjusted to 10%, 30%,50%, 75% or 100% of the maximum detection range.

In one embodiment, the motion sensor outputs one of two states as acontrol instruction, i.e., either motion of a human is detected(STATE 1) or is no longer detected (STATE 2) after a predetermined timeperiod that is adjustable between 5 seconds and 30 minutes. To preventfalse signals due to noises in surrounding environment, the motionsensor has a built-in sensitivity threshold, such that it onlydetermines that a motion is detected (STATE 1), if the detection signalis above the threshold. The motion sensor sends an output of eitherSTATE 1 or STATE 2 to the air purification system (100) which thenadjusts operating conditions or parameters of the UV light subsystem(105) and the air convection means (107) independently.

In one embodiment, the motion sensor sends an output of STATE 1 as aninstruction, when motion of a human is detected, and upon receiving theinstruction, the operation control subsystem (109) sends control commandto carry out one or more operations as follows:

-   -   (a) powering the air purification system (100);    -   (b) having the UV light sources (106) emit UVC rays;    -   (c) having the UV light sources (106) emit near UVA rays at        approximately 405 nm, e.g., by powering on the Near UVA LEDs        (106) alone while keeping the UVC LEDs (106) off;    -   (d) increasing the intensity of any of above UV light sources        (106); and    -   (e) increasing the speed of the air convection means (107).        Above operations may be carried out by the air purification        system (100) independently.

In one embodiment, the motion sensor sends an output of STATE 2 as aninstruction, when motion of a human is not detected for a predeterminedtime period that can be adjusted between 5 seconds and 30 minutes, andupon receiving the instruction, the air purification system (100)carries out one or more operations as follows:

-   -   (a) powering off the Near UVA LEDs (106);    -   (b) powering off the UVC LEDs (106);    -   (c) decreasing the intensity of any of above UV light sources        (106);    -   (d) decreasing the speed of the air convection means (107);    -   (e) powering off the air convection means (107); and    -   (f) powering off the air purification system (100) entirely.        Above operations may be carried out by the air purification        system (100) independently.

In one embodiment, upon receiving the STATE 1 or STATE 2 instruction,the operation control subsystem (109) automatically powers on or off theUV light subsystem (105) and the air convection means (107)simultaneously. In one embodiment, the UV light subsystem (105) remainspowered on, regardless of the STATE 1 and/or STATE 2 instructionsreceived by the operation control subsystem (109). In one embodiment, asa protection for people who are concerned with exposure to UV radiation,the operation control subsystem (109) automatically powers off the UVlight subsystem (105) upon receiving a STATE 1 instruction, and powersthe UV light subsystem (105) on upon receiving a STATE 2 instruction.

In one embodiment, the motion sensor sends an output of STATE 2 as aninstruction, when motion of a human is not detected for a predeterminedtime period that can be field adjusted between 5 seconds and 30 minutesby a switch and/or software. In one embodiment, the motion sensor sendsan output of STATE 2 as instruction, when motion of a human is notdetected for a predetermined time period that can be field adjusted to 5seconds, 30 seconds, 1 minute, 5 minutes, 10 minutes, 20 minutes and 30minutes by a switch and/or software.

In one embodiment, the control command triggered by receipt of eitherthe STATE 1 or STATE 2 instruction is programmable by a user on a remotecontroller, a smart switch, a smart device, a smart home controlappliance, or software built into the operation control subsystem (109).

In one embodiment, the motion sensor sends an output of STATE 1 as aninstruction, when motion of a human is detected, and upon receiving theinstruction, the air purification system (100) automatically sets theair convection means (107) to operate at the high speed. In oneembodiment, the motion sensor sends an output of STATE 2 as aninstruction, when motion of a human is not detected for a predeterminedtime period, and upon receiving the instruction, the air purificationsystem (100) automatically sets the air convection means (107) to alower speed such as the low speed, or powers the air purification system(100) off.

By sending control commands based on received control actions, theoperation control subsystem (109) offers the following control functionsincluding:

-   -   (a) a “timer function” that powers on or off and adjusts any        operating condition or parameter of the air purification system        (100) at an adjustable preset time point or after an adjustable        preset time elapse;    -   (b) an “UV intensity function” that adjusts the intensity of the        UV rays emitted by the UV light sources (106);    -   (c) a “UV wavelength function” that adjusts the wavelength of        the UV rays emitted by the UV light sources (106); and    -   (d) an “air speed function” that adjusts the speed of the air        convection means (107).        A use may access above functions via one or more above-mentioned        sources sending control instructions to the air purification        system (100).

In one embodiment, the air purification system (100) of the presentinvention provides a system for disinfection of air and surfaces throughUVC irradiation that occurs with a line of sight between the UVC sourceand the air or the surface.

In one embodiment, the air purification system (100) provides surfaceand air disinfection for airborne viruses.

In one embodiment, air is propelled by the air convection means (107)and circulates through the air purification system (100), effectivelyreducing the operating temperature of the UV light subsystem (105) andthe UV light sources (106), thus elongating the lifetime of the UV lightsources (106).

In one embodiment, the air purification system (100) of the presentinvention can be instantly turned on or off. In one embodiment, thewavelength of the ultraviolet radiation emitted by the UV light sources(106) can be tuned from 250 nm to 285 nm.

In one embodiment, the UV light sources (106) achieves a longer lifetimeof approximately 30,000 hours, which is superior to Quartz UV Tubes andLamps that usually have lifetime of around 8,000 hours.

In one embodiment, the air purification system (100) monitors theinternal airflow and modulates the intensity of UVC radiation as emittedby the UV light sources (106) to effectively deactivate microorganismssuch as bacteria, viruses, and mold.

In one embodiment, the air purification system (100) has a built-indetector of internal airflow and automatic adjust the power of the UVlight sources (106). In one embodiment, the air purification system(100) automatically increases the power of the UV light sources (106)when flow rate of the internal airflow is detected to be above athreshold.

In one embodiment, the air purification system (100) has a built-in widevoltage range LED driver operating from 100 to 480 Volts for quick andsimple installation.

In one embodiment, the air purification system (100) further comprisesmagnets or clamps for mounts.

In one embodiment, the air purification system (100) comprises a UVCsensor or detector that sends a signal to the LED driver that providespower to the UVC LED light sources to maintain a constant level of UVCintensity in the interior of the air purification system (100).

In one embodiment, the air purification system (100) comprises anairflow sensor or detector that sends a signal to the LED driver thatprovides power to the UVC LED light sources to adjust the power of theUVC light sources.

In one embodiment, the interior of the air purification system (100) ispartially or wholly made of aluminum, which has one or more reflectingsurfaces for maximal reflection of UVC rays. In one embodiment,characteristics of the one or more reflecting surfaces are the same asor similar to those disclosed in WO 2017158989A1.

In one embodiment, the air purification system (100) of the presentinvention comprises a built-in surge protection, which protects the airpurification system (100) from electrical surge during operation. In oneembodiment, the surge protection device is integrated into the UV lightsubsystem (105) and/or the operation control subsystem (109).

In one embodiment, the air purification system (100) of the presentinvention may disinfect surfaces and air within a distance of 3 to 5meters and achieve the almost 100% PGDE Index after a continuous use of10 to 30 minutes.

In one embodiment, the air purification system (100) has one or morethermal sensors (thermistors) coupled to and/or integrated into theoperation control subsystem (109), which sense the operating temperatureof the UV light sources (106) and manages electric power to preventoverheating.

In one embodiment, the power of the UV light sources (106) is adjustedaccording to a predefined program to maintain a PGDE Index substantiallyin a range of 85% to 100%.

In one embodiment, the present invention provides an air purificationsystem that comprises a housing having an inlet for receiving air, anoutlet for exhausting air, and one or more utility openings, wherein anair stream is passable from the inlet to the outlet. The system alsocomprises an air convection means in the housing, which moves the airstream through the inlet from outside into a chamber in the housing, andfurther move the air stream from the chamber to outside through theoutlet. The system further comprises a UV light subsystem within thechamber, comprising a plurality of UV light sources configured to emitUV radiation with adjustable wavelengths to irradiate the air streampassing through the chamber; and an operation control subsystem adaptedto the utility openings on the housing, by which a user controls oradjusts the air convection means and UV light subsystem, wherein whenthe air purification system is in operation, the air stream moved by theair convection means enters the chamber through the inlet, is irradiatedby the UV light sources of the UV light subsystem, and exits through theoutlet, thereby being disinfected.

In one embodiment, the UV light subsystem comprises one or more PCBs formounting the UV light sources in the chamber, wherein the PCBs comprisealuminum, so that heat accumulated in the chamber is efficientlydissipated, thereby lowering the operating temperature of the UV lightsources and elongating the lifetime of the UV light sources.

In one embodiment, the UV light sources emit UVC rays with a wavelengthranging from 200 to 280 nm and UVA rays with a wavelength ofapproximately 405 nm, and wherein the UVA rays are visible to abystander as a safety measure to signal UV leakage from the system.

In one embodiment, the UV light sources have a power of 30 to 150 W, aflux of 10 to 10,000 μW/cm2 so as to achieve an irradiation dosage of atleast 2,500 μW·s/cm2 in the chamber within several seconds to severalminutes of use, and an irradiation of 200 to 3,000 mW for rapid andsubstantially complete disinfection of the air stream.

In one embodiment, the air purification system further comprises an airfiltration means attached to the air convection means, wherein the airfiltration means removes particulates from the air stream before orafter disinfecting the air stream.

In one embodiment, the air purification system further comprises a UVCsensor inside the chamber for detecting the intensity of UVC raysemitted by the UV light sources.

In one embodiment, based on sensory data received from the UVC sensor,the electric power supplied to the UV light sources is modulated tomaintain a constant level of UVC intensity in the chamber.

In one embodiment, 70% of the nominal power supply is provided to new UVlight sources while, when the UVC sensor detects a 10% reduction of theintensity of UVC rays in the chamber of the air purification systemafter use for a period time, the system increases power supplied to theUV light sources to 80% of their nominal power supply.

In one embodiment, the UV light sources with adjustable electric powerhave increased longevity.

In one embodiment, the UV light sources have a rated life of 30,000 to50,000 hours, wherein the rated life is a period of time in which the UVlight sources have an optical output of no less than 70% of the nominalpower output.

In one embodiment, the air purification system achieves a PGDE Index ina range of 85% to 100%.

In one embodiment, the air purification system reduces COVID-19 virus inthe air stream by 99.9%.

In one embodiment, operating conditions and parameters of the UV lightsources and the air convection means are adjusted by a user via theoperation control subsystem.

In one embodiment, the operation control subsystem intelligently adjuststhe operating conditions and parameters based on instructions from theuser saved on a smart home control appliance or encoded in a softwareoperable with the operation control subsystem.

In one embodiment, the UV light sources in the chamber comprise two UVCLED strips facing one another to ensure the most potent irradiation anddisinfection while minimizing UVC leakage from the air purificationsystem.

In one embodiment, the air convection means comprises an airflowdetector for detecting flow rate of air therein, wherein when the flowrate of air reaches a threshold value or a range, the airflow detectorprovides a signal to the operation control subsystem to adjust the powerof the UV light sources.

In one embodiment, the power of the UV light sources is adjusted in away to maintain a PGDE Index substantially in a range of 85% to 100%.

In one embodiment, the interior of the chamber has one or morereflecting surfaces made of aluminum for maximal reflection of UV rays.

In one embodiment, the air purification system further comprises amotion sensor for alarming a person adjacent to or present within apredetermined distance of the air purification system from possibleexposure to the ultraviolet light emitted by the UV light sources due toUV light leakage.

In one embodiment, the motion sensor is a High Frequency Doppler (HFD)sensor.

Throughout this application, various references or publications arecited. Disclosures of these references or publications in theirentireties are hereby incorporated by reference into the application inorder to more fully describe the state of the art to which thisinvention pertains. It is to be noted that the transitional term“comprising”, which is synonymous with “including”, “containing” or“characterized by”, is inclusive or open-ended, and does not excludeadditional, un-recited elements or method steps.

REFERENCES

-   1. Ultraviolet Disinfection Guidance Manual for the Final Long Term    2 Enhanced Surface Water Treatment Rule. EPA 815-R-06-007. United    States Environmental Protection Agency (November 2006).-   2. Murdoch et al., Bactericidal Effects of 405 nm Light Exposure    Demonstrated by Inactivation of Escherichia, Salmonella, Shigella,    Listeria, and Mycobacterium Species in Liquid Suspensions and on    Exposed Surfaces. Scientific World J. Vol 2012, Article ID 137802    (2012).

What is claimed is:
 1. An air purification system, comprising: a housinghaving an inlet for receiving air, an outlet for exhausting air, and oneor more utility openings, wherein an air stream is passable from theinlet to the outlet; an air convection means in the housing, which movesthe air stream through the inlet from outside into a chamber in thehousing, and further moves the air stream from the chamber to outsidethrough the outlet; a UV light subsystem within the chamber, comprisinga plurality of UV light sources configured to emit UV radiation withadjustable wavelengths to irradiate the air stream passing through thechamber, wherein the UV light subsystem comprises one or more PCBs formounting the UV light sources in the chamber, wherein the PCBs comprisealuminum, so that heat accumulated in the chamber is efficientlydissipated, thereby lowering the operating temperature of the UV lightsources and elongating the lifetime of the UV light sources; and anoperation control subsystem adapted to the utility openings on thehousing, by which a user controls or adjusts the air convection meansand UV light subsystem, wherein when the air purification system is inoperation, the air stream moved by the air convection means enters thechamber through the inlet, is irradiated by the UV light sources of theUV light subsystem, and exits through the outlet, thereby beingdisinfected.
 2. The system of claim 1, wherein the UV light sources areUV LEDs emitting UVC rays with a wavelength ranging from 200 to 280 nmand UVA rays with a wavelength of approximately 405 nm, and wherein theUVA rays are visible to a bystander as a safety measure to signal UVleakage from the system.
 3. The system of claim 1, wherein the UV lightsources are UV LEDs having a power of 30 to 150 W, a flux of 10 to10,000 μW/cm² to achieve an irradiation dosage of at least 2,500μW·s/cm² in the chamber within several seconds to several minutes ofuse, and an irradiation of 200 to 3,000 mW for rapid and substantiallycomplete disinfection of the air stream.
 4. The system of claim 1,further comprising an air filtration means attached to the airconvection means, wherein the air filtration means removes particulatesfrom the air stream before or after disinfecting the air stream.
 5. Thesystem of claim 1, wherein the UV light sources have a rated life of30,000 to 50,000 hours, wherein the rated life is a period of time inwhich the UV light sources have an optical output of no less than 70% ofthe nominal power output.
 6. The system of claim 1, wherein operatingconditions and parameters of the UV light sources and the air convectionmeans are adjusted by a user via the operation control subsystem, andthe operation control subsystem intelligently adjusts the operatingconditions and parameters based on instructions from the user saved on asmart home control appliance or encoded in a software operable with theoperation control subsystem.
 7. The system of claim 1, wherein the airconvection means comprises an airflow detector for detecting flow rateof air therein, wherein when the flow rate of air reaches a thresholdvalue or a range, the airflow detector provides a signal to theoperation control subsystem to adjust the power of the UV light sources.8. The system of claim 7, wherein the power of the UV light sources isadjusted to maintain a PGDE Index substantially in a range of 85% to100%.
 9. The system of claim 1, wherein the interior of the chamber hasone or more reflecting surfaces made of aluminum for maximal reflectionof UV rays.
 10. The system of claim 1, further comprising a motionsensor for alarming a person adjacent to or present within apredetermined distance of the air purification system from possibleexposure to the ultraviolet light emitted by the UV light sources due toUV light leakage.
 11. The system of claim 10, wherein the motion sensoris a High Frequency Doppler (HFD) sensor.
 12. An air purificationsystem, comprising: a housing having an inlet for receiving air, anoutlet for exhausting air, and one or more utility openings, wherein anair stream is passable from the inlet to the outlet; an air convectionmeans in the housing, which moves the air stream through the inlet fromoutside into a chamber in the housing, and further moves the air streamfrom the chamber to outside through the outlet; a UV light subsystemwithin the chamber, comprising a plurality of UV light sourcesconfigured to emit UV radiation with adjustable wavelengths to irradiatethe air stream passing through the chamber; a UVC sensor inside thechamber for detecting the intensity of UVC rays emitted by the UV lightsources, wherein, based on sensory data received from the UVC sensor,the electric power supplied to the UV light sources is modulated tomaintain a constant level of UVC intensity in the chamber; and anoperation control subsystem adapted to the utility openings on thehousing, by which a user controls or adjusts the air convection meansand UV light subsystem, wherein when the air purification system is inoperation, the air stream moved by the air convection means enters thechamber through the inlet, is irradiated by the UV light sources of theUV light subsystem, and exits through the outlet, thereby beingdisinfected.
 13. The system of claim 12, wherein, 70% of the nominalpower supply is provided to new UV light sources while, when the UVCsensor detects a 10% reduction of the intensity of UVC rays in thechamber of the air purification system after use for a period time, thesystem increases power supplied to the UV light sources to 80% of theirnominal power supply.
 14. The system of claim 12, wherein the UV lightsources are UV LEDs emitting UVC rays with a wavelength ranging from 200to 280 nm and UVA rays with a wavelength of approximately 405 nm, andwherein the UVA rays are visible to a bystander as a safety measure tosignal UV leakage from the system.
 15. The system of claim 12, whereinthe UV light sources are UV LEDs having a power of 30 to 150 W, a fluxof 10 to 10,000 μW/cm² to achieve an irradiation dosage of at least2,500 μW·s/cm² in the chamber within several seconds to several minutesof use, and an irradiation of 200 to 3,000 mW for rapid andsubstantially complete disinfection of the air stream.
 16. The system ofclaim 12, further comprising an air filtration means attached to the airconvection means, wherein the air filtration means removes particulatesfrom the air stream before or after disinfecting the air stream.
 17. Thesystem of claim 12, wherein the UV light sources have a rated life of30,000 to 50,000 hours, wherein the rated life is a period of time inwhich the UV light sources have an optical output of no less than 70% ofthe nominal power output.
 18. The system of claim 12, wherein operatingconditions and parameters of the UV light sources and the air convectionmeans are adjusted by a user via the operation control subsystem, andthe operation control subsystem intelligently adjusts the operatingconditions and parameters based on instructions from the user saved on asmart home control appliance or encoded in a software operable with theoperation control subsystem.
 19. The system of claim 12, wherein the airconvection means comprises an airflow detector for detecting flow rateof air therein, wherein when the flow rate of air reaches a thresholdvalue or a range, the airflow detector provides a signal to theoperation control subsystem to adjust the power of the UV light sources.20. The system of claim 19, wherein the power of the UV light sources isadjusted to maintain a PGDE Index substantially in a range of 85% to100%.
 21. The system of claim 12, wherein the interior of the chamberhas one or more reflecting surfaces made of aluminum for maximalreflection of UV rays.
 22. The system of claim 12, further comprising amotion sensor for alarming a person adjacent to or present within apredetermined distance of the air purification system from possibleexposure to the ultraviolet light emitted by the UV light sources due toUV light leakage.
 23. The system of claim 22, wherein the motion sensoris a High Frequency Doppler (HFD) sensor.
 24. An air purificationsystem, comprising: a housing having an inlet for receiving air, anoutlet for exhausting air, and one or more utility openings, wherein anair stream is passable from the inlet to the outlet; an air convectionmeans in the housing, which moves the air stream through the inlet fromoutside into a chamber in the housing, and further moves the air streamfrom the chamber to outside through the outlet; a UV light subsystemwithin the chamber, comprising a plurality of UV light sourcesconfigured to emit UV radiation with adjustable wavelengths to irradiatethe air stream passing through the chamber, wherein the UV light sourcesin the chamber comprise two UVC LED strips facing one another to ensurethe most potent irradiation and disinfection while minimizing UVCleakage from the air purification system; and an operation controlsubsystem adapted to the utility openings on the housing, by which auser controls or adjusts the air convection means and UV lightsubsystem, wherein when the air purification system is in operation, theair stream moved by the air convection means enters the chamber throughthe inlet, is irradiated by the UV light sources of the UV lightsubsystem, and exits through the outlet, thereby being disinfected.